A completely randomized design with three replicates was used to evaluate the addition effects of 0.5% urea, 0.5% calcium carbonate, 0.5% urea plus 0.5% calcium carbonate, and bacteria culture (according to producer recommendations) on quality of four hybrids sorghum silages (BR700, BR701, BR601 e AG2002). All hybrids ensiled with no additives were used as the control group. The pH and the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, cellulose, lignin, soluble carbohydrates, lactic and acetic acids, and the in vitro dry matter digestibility (IVDMD) values were determined. Three samples of each original material (MOR) were collected and analyzed. Sixty "PVC" experimental silos with 10cm of internal diameter and 50cm of length, three by treatment, were used. The silos were open after 56 days of fermentation. The results of silages containing calcium carbonate or bacteria culture were, in general, similar to the control group (without additives). The addition of urea and urea plus calcium carbonate to silages improved their CP contents (P<0.05). The addition of urea plus calcium carbonate did not improve the CP contents of silages in relation to the addition of only urea. The addition of urea can be recommended for silages of BR700, BR601 and AG2002 hybrids.
urea; bacteria culture; calcium carbonate
